import os
def mim(key, mst):
    mini = float('+inf')
    index = 0
    for i in range(1, len(key)):
        # print("I",key[i])
        if not mst[i] and key[i] < mini:
            mini = key[i]
            index = i
    # print("ndggkndg",index,mini)
    return index

def prims(n, edges, s):
    adjList = {v: [] for v in range(1, n+1)}
    
    for u, v, w in edges:
        adjList[u].append((v, w))
        adjList[v].append((u, w))
    parent =[0]*(n+1)
    key = [float('+inf')]*(n+1)
    mst = [False]*(n+1)
    key[s]=0
    parent[s]=-1
    mst[0]= True
    
    while not all(mst):
        node = mim(key, mst)
        # print("node",node)
        mst[node] = True
        for x, z in adjList[node]:
            # print(node,x,key[x])
            if mst[x]==False and key[x] >z:
                # print(node, x,key[x])
                key[x]=z
                parent[x] = node
    # print(key)
    # print(parent)
    return sum(key[1:])